Acrylonitrile butadiene styrene (ABS) is a thermoplastic which is primarily used to make light, rigid, molded products such as piping, musical instruments, automotive body parts, whitewater canoes, kitchen appliances and toys. ABS is a high molecular weight organic compound that includes nitrogen atoms. ABS is derived from acrylonitrile, polybutadiene and styrene. Acrylonitrile are synthetic monomers produced from propylene and ammonia and butadiene is a petroleum hydrocarbon obtained from butane. Styrene monomers, derived from coal, are commercially obtained from benzene and ethylene from coal. ABS is a copolymer made by polymerizing styrene and acrylonitrile in the presence of polybutadiene. Typical proportions can vary from 15 to 35% acrylonitrile, 5 to 30% polybutadiene and 40 to 60% styrene.
ABS also has good electrical properties that remain fairly consistent over a wide range of frequencies. These properties are minimally affected by temperature and atmospheric humidity in the acceptable operating range of temperature.
ABS offers many advantages. One of the advantages of ABS is that this material combines the strength and rigidity of acrylonitrile and styrene polymers with the toughness of the polybutadiene rubber. ABS can be made by blending a mixture of butadiene-acrylonitrile rubber with styrene-acrylonitrile resins. By varying the process involved and/or the composition of each constituent, properties of the ABS can be varied accordingly. A variety of modifications can be made to improve impact resistance, toughness and heat resistance. For instance, the impact resistance can be amplified by increasing the proportions of polybutadiene in relation to styrene and acrylonitrile although this causes changes in other properties.
There are many existing methods and techniques for preparing ABS. For example, in U.S. Pat. No. 5,278,253, a process for the continuous preparation of ABS polymers by free-radical-initiated polymerization of styrene and acrylonitrile in the presence of polybutadiene is disclosed. The patent discusses methods for preparing ABS in the presence or absence of solvent and it includes the use of at least 60 to 90% by weight of at least one vinylaromatic monomer, at least 10 to 40% by weight of at least one ethylenically unsaturated monomer and 5 to 30% by weight (based on the total of monomers) of polybutadiene. A reactor cascade comprising at least 3 stirred reactors are used and at least some of which contain internal cooling tubes for dissipating the heat of polymerization, at from 50 to 180° C. The advantage of the process in this patent is that a reasonably high degree of grafting of the rubber is achieved without any problems of heat dissipation, reactor deposits or premature crosslinking.
There are several other different methods, processes and techniques for preparing or producing ABS or ABS-based compositions or products. However, there are various drawbacks or limitation associated with these existing methods, processes and techniques. In particular, these existing methods, processes and techniques involve a number of complicated steps. The more steps involved, the lower the efficiency yield of the resultant product (for example, the ABS or ABS-based compositions or products). Furthermore, the use of polybutadiene (or any other types of synthetic rubbers) in conventional methods of producing ABS or ABS-based compositions or products has adverse effects on the environment. This is mainly due to the large quantities of chemical pollutants produced as a result of synthesizing polybutadiene. Additionally, synthesizing polybutadiene involves high production costs, primarily associated with high material costs, apparatus and manpower.
It is therefore desirable to provide a solution to address at least one of the foregoing problems associated with conventional methods, processes and techniques for preparing or producing ABS or ABS-based compositions or products.